What could no Power LED mean?

[How it happen]
Last week when I was using my PC my PC suddenly got a BSOD, I pressed the reset button and there was no screen. I switched off the whole system, played around with the RAM slots (cause I think that's where I thought the problem lies) then switch on. There was the smell of a smoke. I quickly switch the whole PC off, re-adjust the RAM slots and switch on again. This time, the HDD LED was lit on but the POWER LED is not. I thought it could be the fault of the mobo, so I bought a new mobo. I installed the new mobo, with the old CPU and RAM, and the same thing happened.

[Question]
What does it mean when the Power LED is not lit when the HDD LED is lit? I'm pretty sure it isn't the problem of the pins. Can someone help me deduce which component is causing the problem? Thanks!

Ouch! When you smell smoke try to isolate the individual component ,if you can eg scortch marks,smell each item uninstalled.
A bad power supply could do what you described.
I just hope you have not fried the new Mb with whatever the bad item is.
I think I would then try to start with threadbare components and install 1 at a time after a test.

Hi, thank you for replying! I smelled each of the components... and figured that it was the chipset which burnt. If I used a new motherboard, it means that I used a new chipset. However, the same error still appears - the power LED did not light up - which makes me think it's a CPU problem. Can you or anyone confirm with me? Thanks lots!